Latest firmware 2.7.4.24. When sending from Outlook or iOS clients, cannot send, error AUP-CXDNS. Shutting off wireless circumvents the issue. Any DNS setting in the ORBI that might correct this? Thanks.

Will do, though since that would impact the household working from home, it will be (much) later today. Thanks.

Same failures when using the alternative DNS servers suggested. Now pursuing this as an issue with my ISP, which at the moment is a different ISP than my email provider.Thanks for the help, and I'll share more later whether fixed or not.

Ekhalil, you have it right, I believe, in both of your recent posts. Had the opportunity to test from Cox ISP with RBR50, and email is sent without issue. Seems clear that issue is with ISP from my original report and testing. Thanks again, all.

Google search turned up a number of hits, mostly involving Cox Cable. Such as: https://forums.cox.com/forum_home/internet_forum/f/internet-forum/29627/cxdns-error-when-sending-mail-from-my-outlook-365-account

What DNS settings do you currently have in Orbi? Please check this in the Orbi web GUI (orbilogin.com) under >> ADVANCED >> Setup >> Internet Setup >>

RBK50 DNS errors when sending to SMTP server

11 Replies

CrimpOn
Guru
Sep 11, 2022
Google search turned up a number of hits, mostly involving Cox Cable.

Such as: https://forums.cox.com/forum_home/internet_forum/f/internet-forum/29627/cxdns-error-when-sending-mail-from-my-outlook-365-account
- SteveHansen26
  Guide
  Sep 11, 2022
  My ISP is in fact Cox, but the fact that sending email works normally when not connected to WiFi makes it hard (not impossible) to blame them.
ekhalil
Master
Sep 11, 2022
What DNS settings do you currently have in Orbi? Please check this in the Orbi web GUI (orbilogin.com) under >> ADVANCED >> Setup >> Internet Setup >>
- SteveHansen26
  Guide
  Sep 11, 2022
  Have not changed from the defaults, so:
  No Logon required
  IP address assignment and DNS settings coming automatically from ISP, two DNS servers provided by my ISP
  Default Router MAC address
  No DHCP options
  No VLAN ID specifications
  No Dynamic DNS settings
  
  I will add that errors occur whether connected via ethernet or WiFi.
  - ekhalil
    Master
    Sep 11, 2022
    For a test, please try to select “Use These DNS Servers” and set the dns servers to primary 1.1.1.1 and secondary 8.8.8.8 then click on Apply

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RBK50 DNS errors when sending to SMTP server